1. Field of the Invention
The present invention relates to drivers for light emitting diodes (LEDs), more particularly to drivers for LEDs of different colors.
2. Art Background
With the advent of red, green, and blue light emitting diodes (LEDs) their use in color displays has increased. Separate red, green, and blue LEDs can be combined to produce many colors and intensities of light, for example white light for backlighting displays. Ideally to obtain color balance and provide brightness control while maintaining that color balance, the individual red, green, and blue devices would have the same characteristics, such as efficiency, light output for a given drive voltage and current, and so on. This is unfortunately not the case. LEDs for the different primary colors have widely differing drive requirements, luminous outputs, and efficiencies. Additionally, process variations result in performance differences among LEDs of the same color. Consequently, means must be provided in the LED driver circuitry to allow these differing characteristics to be matched.
What is needed is an LED driver design for incorporating into an integrated circuit that allows varying LED characteristics to be easily accommodated.